U.S. Pat. No. 4,400,340 and U.S. Pat. No. 4,426,502 disclose the production of a molded article by injecting two kinds of reactive solutions, one of which comprises a norbornene-type monomer such as dicyclopentadiene and the catalyst component of a metathesis polymerization catalyst system and the other comprises a norbornene-type monomer and the activator component of the catalyst system using impingement mixing into a mold in which said liquid mixture is metathesis polymerized in bulk (called "RIM process" hereinafter). RIM process is a low pressure one-step or one-shot injection process and the liquid mixture injected into the mold polymerizes rapidly to form a molded article. Thus, there are easily and cheaply produced large-sized molded articles from norbornene-type monomers such as dicyclopentadiene by RIM process.
U.S. Pat. No. 4,598,102 discloses the addition of reinforcing agents or fillers such as glass, wollastonite, mica, carbon black, talc and calcium carbonate into the metathesis polymerizable composition of cyclic olefin monomers.
Although such reinforcements are added to improve mechanical and physical properties, such as flexural modulus and strength, it has been observed that the addition of them does not necessarily achieve such improvement effectively. It is known that affinity between reinforcements and matrix polymers influences mechanical and physical properties of the composites thereof and that good affinity generally improves those properties.
There are many references in the prior art to increasing the affinity between the reinforcements and the matrix polymers. One of the methods commonly used is the treatment of the reinforcements or the fillers with a coupling agent. Among coupling agents, there have been used most commonly silane coupling agents, having at least one group, which is hydrolyzable to silanol group and is bonded to silicon atom, and at least one group which imparts good affinity to the matrix polymers.
The silanol group may readily react with hydroxyl groups or other active groups existing on the surface of the reinforcements.
Thus, the silane couplers can act as a go-between of the matrix and the reinforcements.
As a matter of course, the groups which impart the good affinity to the matrix polymers should differ depending on the kinds of the polymers.
It has been found that vinylsilanes, for example, which were used previously as couplers for unsaturated polyesters (UPE), are not so effective. Methacryl silanes, therefore, are now used predominantly as couplers for UPE instead of vinylsilane.
Aminoalkyl silane couplers and epoxy-containing silane couplers are used for epoxy resins, polyurethanes, polyamides, polyimides, phenolic resins and the like. Chloroalkylsilanes and mercapto-group-containing silane couplers are suitably used with such rubbers as EPDM, SBR, NR and polychloroprenes.
Silane couplers which impart good affinity to the above mentioned metathesis-polymerized polymers with fillers have been required to prepare composites having good properties.
So far as we are aware of, there was available no prior information on silane couplers imparting such good affinity to the metathesis polymerized polymers.
We have studied and tested the coupling effect of many silanes as to whether the silanes can increase the affinity of the metathesis polymerized polymers with the fillers and reinforcing materials or not. The tests of the coupling properties were carried out, for example, by measuring the bonding strength between the metathesis polymerized polymers and a glass plate pretreated with one of the silanes.
As a result, we have found that, among many silanes, particular silanes having at least one hydrolyzable group bonded to silicon atom and at least one unsaturated group of the formula R.sup.1 --CH.dbd.CH--R.sup.2 --, wherein R.sup.1 is hydrogen or alkyl group of 1-6 carbon atoms, and R.sup.2 is a single bond or alkylene group of 1-6 carbon atoms, which is bonded to silicon atom, having very excellent coupling properties and increases magnificently the affinity of the metathesis polymerized polymers with the fillers and reinforcing materials to reinforce largely the polymers. The selective and excellent coupling properties of these silanes for the metathesis polymerized polymers are beyond expectation, since these silanes have been seldom used recently to treat the reinforcements for the usual polymers such as UPE, epoxy resins, polyurethane, phenol resins, polyamide and the like.
Further, it is an unexpected finding that said particular silanes do not substantially damage the activity of the metathesis polymerization catalyst system, when used in the metathesis polymer systems.
Therefore, it is an object of the present invention to provide a molded article which is reinforced by fillers pretreated with said particular silanes.
A further object of the present invention is the provision of a process for producing the reinforced molded articles containing the fillers.